Machine for cleaning small parts



Oct. 27, 1959 G. G. GRUETTNER ET AL 2,910,390

MACHINE FOR CLEANING SMALL PARTS Filed June 29, 1956 2,910,390 ratemea Oct. 27, 1959 2,910,390 MACHINE FOR CLEANING SMALL PARTS Gerhard G. Gruettner, North Arlington, N.J., and Donald R. Church, Wantagh, and Morris Kenny, Levittown, N.Y., assignors, by mesne assignments, to Hermes Sonic Corporation, New York, N.Y., a corporation of New York Application June 29, 1956, Serial No. 594,867

3 Claims. (Cl. 134-1) The present invention relates to a machine for cleaning small parts, and more particularly to a machine for cleaning watches and other mechanisms comprising small and intricate parts and assemblies.

The cleaning of small parts and assemblies made up of small parts has long presented a problem. Conventionally, the cleaning of watch movements and other assemblies made from tiny precise parts is effected by rigorous mechanical agitation, while such assemblies and parts are immersed within a cleaning solution or solvent, and has not proven to be satisfactory. Watch oils and the other types of lubricants used for such assemblies and parts decompose oxidatively and otherwise during the passage of time and the resultant gums, sediments, or precipitates tend to cling to the Watch parts and are not easily removed. Long experience with the best of mechanical watch cleaning mechanisms has shown that there are many types of watch movements which cannot be satisfactorily cleaned by conventional mechanical agitational watch cleaning equipment.

More recently, the use of ultrasonic watch cleaning equipment has been suggested, but such equipment has likewise not proven satisfactory for many types of watches. It has been found that many forms of contaminants and dirt deposits resist cleaning by present day ultrasonic watch cleaning devices.

This invention has as an object the provision of a machine for cleaning small parts, and assemblies made up of small parts, and, in particular, watch movements.

This invention has as another object the provision of a machine which may accomplish the complete cleaning of watch movements that may not be readily cleaned by any other known mechanism or device.

Other objects will appear hereinafter.

For the purpose of illustrating the invention there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

Figure 1 is a perspective view of the entire unit of the present invention.

Figure 2 is a fragmentary sectional view taken on line 2-2 of Figure 1.

Figure 3 is a View taken on line 3-3 of Figure 2.

Referring to the dnawings, denotes a base to which is afiixed an upright or standard 12. A bracket 14 sustains an electric motor 16 upon upright 12. Bracket 14 may be adjustably rotated and adjustably raised or lowered upon upright 12. The base 10 is provided with a plurality of tank-supporting recesses or sockets 18, which may receive tanks of the type designated as tank 20.

A Watch cleaning liquid is disposed within tank 20. Such watch cleaning liquid may comprise an organic solvent or an aqueous detergent solution, a wide variety of suitable watch cleaning liquids being known to those skilled in the art.

A shaft 22 depends from motor 16. To the shaft 22 may be fixed a holder designated generally by the numeral 24. Holder 24 comprises a ring 26 connected by radial vane arms 28 to hub 30 which is engaged, as by threaded engagement, with shaft 22 of motor 16.

The vane arms 28 are flared and curved in their center portions 31 so as to act as propellers to force cleaning solutions downwardly. The outer ends of vane arms 28 are cut away to form reduced portions 32.

A basket 34 of wire mesh such as of aluminum, stainless steel, or Monel mesh is provided with upwardly extending hook-shaped brackets 36 which are integral with the annular rim 38 of the basket 34. The brackets 36 are provided with a horizontal element 39 and a downwardly extending lug 40. In this manner the hook shaped bracket 36 may be hooked over the reduced portion 32 of vane arms 28 permitting the basket 34 to be hung on the reduced portion 32 of vane arms 28 and preventing any relative rotary movement of the basket 34 in respect to the vane arms 28.

The underside of the vane arms 28 may be provided with leaf springs 42 which may be used to position a cover 44 formed of wire mesh and having an annular rim in position on top of basket 34, the leaf springs 42 bearing on the annular rim of the cover 44. Basket 34 may contain one or more small wire mesh baskets 47 disposed therewithin.

A basket element 46, which may be provided with one or more wire mesh cups for retaining very small parts separate from the prime contents of basket 34, may also be mounted on the annular rim 38 of the basket 34 be neath wire mesh cover 44.

The basket 34 is retained within tank 20 at a predetermined and exact level beneath the surface of the liquid within tank 20. Thus, marker means may be provided on shaft 22 which may be aligned with the cover 48 of tank 20 for ascertaining the proper height at which basket 34 is to be positioned.

The tank 20 is provided with a pair of ultrasonic transducer elements designated generally by the numerals 50 and 52. As shown in Figure 1, the transducers 50 and 52 are angularly disposed in respect to each other, preferably at an angle of about when, as in the illustrated embodiment, two transducers 50 and 52 are utilized.

The subject invention contemplates the utilization of a plurality of transducers, and wheremore than two transducers are used, preferably, the transducers should be distributed more or less evenly about the peripheral portion of the tank 20. For example, where three transducers are utilized, the transducers should be angularly positioned at an angle of about in respect to each other. The transducers 50 and 52 are not placed opposite each other, and are not in the same horizontal plane, instead transducer 50 is positioned somewhat above transducer 52. Preferably, the radial centers of transducers 50 and 52 are spaced in height from each other at a vertical distance of about one half the diameter of the radiating surface of one of the transducers.

When more than two transducers are utilized, the transducers should in all cases include at least a pair of transducers which are in stepwise relationship to each other, that is a pair of transducers, one of which is somewhat above the other, as in the illustrated embodiment in which but two transducers are illustrated.

In the illustrated embodiment each of the transducers 50 and 52 are of the same general construction so that a description of transducer 50 will adequately serve to describe transducer 52.

The transducer 50 includes a disc element 54 formed from a piezoceramic material, such as barium titanate,

or other piezoceramic material, or piezoelectric material, or natural or synthetic crystal, a wide variety of which are known to those skilled in the art. The discelement 54 is provided with thin coatings or films of silver or like conductor designated 55a and 55b in a manner readily understood by one skilled in this art so that it may function as a transducer for producing elastic vibratory energy of ultrasonic frequency. Silver coating 55a covers the inner face of disc element 54 and is juxtaposed to the metal plug 56 and extends over to the disc elements peripheral edge. Silver coating 55b, which is separate and distinct from silver coating 55a, is disposed on the outer face of disc element 54. A wide variety of frequencies may be used in the device of the subject invention, and the dimensioning of disc element 54 to produce the selected frequencies may be accomplished by means well known to those skilled in this art.

In place of a piezoceramic transducer, a magnetostrictive transducer of conventional design formed from nickel, Permendur, Alfenol, or the like may be substituted.

The disc element 54 engages the back of the metal plug 56, which is formed of aluminum, stainless steel, or the like, the metal plug being wedged within an annular flange 58 in the side of tank 20. It is most advantageous to have plug 56 project into tank as shown in Figure 2. Plug 56 forms a baffle within tank 26 and aids in preventing a void when the liquid is rapidly agitated. An O-ring 60 is seated in groove 62 and prevents leakage of liquid from tank 20 about metal plug 56.

Disc element 54 is provided with electrical leads 64a and 64b. Leads 64a and 64b are attached to the silver coating 55a at .the peripheral edge of disc element 54, which, as above-noted, extends to the inner face of disc element 54 juxtaposed to the metal plug 56. Disc element 54- is also provided with electrical lead 66 which is joined to silver coating 5511. Lead 66 is supported by brace 72 in the manner set below. Disc element 54 is also supported by supports 68 and 70 which are threadably received in metal plug 56. Supports 68 and 70 carry a backing element 69 preferably formed of a non-conducting plastic, such as the plastic Bakelite, a urea-formaldehyde resin manufactured by Union Carbide and Carbon Corporation, New York, New York, or similar plastic. A brace 72 is provided for disc element 54, the brace 72 comprising a plastic pillow block 74 formed from an electrical and acoustic insulating material, which engages the rear face of disc element 54.

The lug 73 for lead 66 is carried on brace '72 and the lead 66 is disposed intermediate the pillow block 74 and silver coating 55b. Flange 58 is provided with a cover 76, which may be threadably or otherwise secured thereto.

The leads 64a and 64b and '66 extend to disc element 54 from a conduit 78, which is connected to generator 80. Preferably, as shown in the illustrated embodiment, the conduit 78 extends through the wall of flange 58 after having provided similar leads for transducer 52.

The generator may be of any conventional design, a wide variety of such generators being known to those skilled in this art. Preferably, generator 80 should be of a design that transmits energy of a somewhat varying frequency to the disc element 54 of transducers and 52. Thus, we have found that by varying the frequency by as little as three-tenths of one percent, that is by varying the frequency of the transducers within a range of three kilocycles per second, when the transducers are operating at a frequency of about a megacycle per second, improved results can be obtained.

While we do not understand why improved results are obtained by varying the frequency within even so narrow a range as that set forth above, it is our present belief that by varying the frequency we are eliminating the presence of shadows or dead spots" within the cavitated liquid used for cleaning the assemblies or parts held in basket 34.

Controls 82 for starting and stopping the motor 16 and for heating the recesses 18 are provided in base 10'.

The operation of the device of the present invention is as follows:

Watch movements, watch parts, or other precision small parts are inserted within basket 34 and lowered within tank 20 to the level above-indicated, namely where the basket 34- is opposite the transducers 50 and 52 and beneath the upper level of the watch cleaning liquid. The motor 16 is started and rapidly rotates. Simultaneously, or shortly thereafter transducers 50 and 52 are energized by generator 80. Due to the stepwise positioning of the transducers 5t) and 52 in the manner indicated, intense rotational forces are generated by the ultrasonic energy emitting from the transducers 50 and 52, in addition to the general cavitation of the watch cleaning liquid within tank 26. The combined mechanical rotation due to the rotation of shaft 22, the downward urging of the watch cleaning liquid due to the action of the flared center portions 31 of vane arms 28, and the ultrasonic rotation and general cavitation of the Watch cleaning liquid within tank 20 produces a cleaning action upon the elements being cleaned within basket 34 superior to that which may be achieved by any analogous form of apparatus known to us.

After the cleaning has been completed, shaft 22 and casket 34 are preferably raised and immersed in one or more additional tanks containing a rinsing solution or a solvent. Preferably, this rinse tank is of similar construction as that of tank it). After rinsing has been achieved in the rinse tank, the shaft 22 and basket 34 are again raised and transferred to a drying stage where the rinsing solution is preferably withdrawn through the combined action of heat and mechanical rotation.

The present invention may be embodied in, other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the lnvention.

We claim:

1. A device for cleaning small parts so as to remove foreign matter therefrom which comprises a tank, a depending rotatable shaft disposed within said tank, a perforated basket formed from wire mesh carried on the end of said shaft at a spaced distance above the floor of said tank, a propeller on said shaft disposed above said basket, the blades of said propeller being angularly positioned so as to urge liquid within the tank downwardly, a plurality of transducers for producing ultrasonic elastic vibratory energy carried on the wall of said tank at a level juxtaposing said transducers to at least a portion of said perforated basket, at least two of said transducers being arcuately offset from each other at an angle of at least ninety degrees and vertically offset from each other by a vertical distance of about one-half of the radiating surface of one of said transducers, each of said transducers including a baffie which projects into the interior of the tank, the radiating face of each transducer being perpendicular to the plane occupied by the propeller, the vertical offset of at least two of the transducers being suflicient to permit the application of the greatest amount of vibratory energy from said transducers to different vertical portions of said basket, with the radiating faces of each of said transducers being spaced a distance above the floor of said tank so as to permit foreign matter to fall to the floor of said tank. i

2. A device in accordance with claim 1 in which the transducers vibrate at a frequency of about 1 megacycle per second.

3. A device in accordance with claim 2 in which the frequency of the transducers is varied within a range of three kilocycles per second.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Regero May 2, 1933 Moser Jan. 28, 1947 5 Fruth Apr. 26, 1949 Van Valkenburg Feb. 2, 1954 Bradfield July 27, 1954 Massa Feb. 15, 1955 Gander Aug. 28, 1956 10 6 FOREIGN PATENTS 280,243 Switzerland Apr. 16, 1952 305,341 Switzerland Apr. 16, 1955 OTHER REFERENCES Silent Soun (Guilfoyle), published by The Wall Street Journal, April 14, 1954. 

1. A DEVICE FOR CLEANING SMALL PARTS SO AS TO REMOVE FOREIGN MATTER THEREFROM WHICH COMPRISES A TANK, A DEPENDING ROTATABLE SHAFT DISPOSED WITHIN SAID TANK, A PERFORATED BASKET FORMED FROM A WIRE MESH CARRIED ON THE END OF SAID SHAFT AT A SPACED DISTANCE ABOVE THE FLOOR OF SAID TANK, A PROPELLER ON SAID SHAFT DISPOSED ABOVE SAID BASKET, THE BLADES O F SAID PROPELLER BEING ANGULARLY POSITIONED SO AS TO URGE LIQUID WITHIN THE TANK DOWNWARDLY, A PLURALITY OF TRANSDUCERS FOR PRODUCING ULTRASONIC ELASTIC VIBRATORY ENERGY CARRIED ON THE WALL OF SAID TANK AT A LEVEL JUXTAPOSING SAID TRANSDUCERS TO AT LEAST A PORTION OF SAID PERFORATED BASKET, AT LEAST TWO OF SAID TRANSDUCERS BEING ARCUATELY OFFSET FROM EACH OTHER AT AN ANGLE AT LEAST NINETY DEGREES AND VERTICALLY OFFSET FROM EACH OTHER BY A VERTICAL DISTANCE OF ABOUT ONE-HALF OF THE RADIATING SURFACE OF ONE OF SAID TRANSDUCERS, EACH OF SAID TRANSDUCERS INCLUDING A BAFFLE WHICH PROJECTS INTO THE INTERIOR OF THE TANK, THE RADIATING FACE OF EACH TRANSDUCER BEING PERPENDICULAR TO THE PLANE OCCUPIED BY THE PROPELLER, THE VERTICAL OFFSET OF AT LAST TWO OF THE TRANSDUCERS BEING SUFFICIENT TO PERMIT THE APPLICATION OF THE GREATEST AMOUNT OF VIBRATORY ENERGY FROM SAID TRANSDUCERS TO DIFFERENT VERTICAL PORTIONS OF SAID BASKET, WITH THE REDIATING FACES OF EACH OF SAID TRANSDUCERS BEING SPACED A DISTANCE ABOVE THE FLOOR OF SAID TANK SO AS TO PERMIT FOREIGN MFATTER TO FALL TO THE FLOOR OF SAID TANK. 